An epoxidation catalyst is understood to be a catalyst which catalyzes the production of an epoxy group containing compound. One process comprises contacting organic hydroperoxide and alkene with a heterogeneous epoxidation catalyst and withdrawing a product stream comprising alkylene oxide and an alcohol.
Catalysts for the manufacture of an epoxy group containing compound are known. EP-A-345856 describes the preparation of such a catalyst comprising impregnating a silicon compound with a stream of gaseous titanium tetrachloride preferably comprising an inert gas. In the example, it is mentioned that dried silica is used.
U.S. Pat. No. 6,114,552 teaches the use of a high surface area silica support or the like having a surface area greater than 1100 m2/g in preparing epoxidation catalysts. The high surface area solid is impregnated with either a solution of a titanium halide in a non-oxygenated hydrocarbon solvent or a gas stream of titanium tetrachloride. It is mentioned that it is desirable to dry the silica support prior to impregnation, for example by heating for several hours at a temperature of at least 200 to 700° C. The exemplified silica supports, to be impregnated with gaseous titanium tetrachloride, were dried at 450° C. in air.
U.S. Pat. No. 5,932,751 describes the preparation of titanium on silica catalysts in which the silica has been washed prior to the deposition of the titanium component thereon. A solution is used for depositing the titanium component.
There is a continuous interest in improving the selectivity of epoxidation catalysts in general, and more specifically of catalysts for the preparation of alkylene oxide.